Organized by astronomy-education projects The World at Night (TWAN) and Global Astronomy Month, the contest honors pictures that meet one of two criteria: "either to impress people on how important and amazing the starry sky is, or to impress people on how bad the problem of light pollution has become." In total, ten winners were announced May 9 in either the "Beauty of the Night Sky" or "Against the Lights" category.
To achieve the contest goals, organizers asked for "landscape astrophotography"—pictures of world landmarks against the night sky. This style "brings Earth and sky into one frame, and it's a bridge between the night sky and the ... environment," TWAN founder and contest judge Babak Tafreshi said in an email to National Geographic News.
"If we considered dark, starry skies a part of nature and our living world heritage, then we would try to preserve it like the other parts of nature."
Twinkling stars over the Austrian Alps compete against the bright glow of a mist-covered town near Lake Traunsee in a February 17, 2010, picture.
Overall, images in the "Against the Light" category "try to display how the beauties of the night sky are being vanished away by increasing lights in our modern life," TWAN's Tafreshi said. "Many of these lights are either not directed toward the ground in the right way or not necessary in those locations."
This picture of the Alps impressed the contest judges because it "has a very good balance between the starry sky and the lights," Tafreshi said. "Sky is affected partly by those village lights but not vanished away. So the beauty of nature exists above the lights."
A tree seems to bend in a galactic breeze in a July 2010 picture of the central bulge of the Milky Way taken from Australia.
Our solar system lies in one of the galaxy's spiral arms, about halfway from the galactic center. Recent studies show that the Milky Way's dusty heart houses a supermassive black hole.
"The position of the Milky Way in this image—lying horizontally, just above the horizon—gives the sense that it's just beyond arm's reach. Walk to the horizon, and instead of falling off the edge of the Earth, you can step into the rest of the galaxy," said contest judge Mike Simmons, president of Astronomers Without Borders, a TWAN co-founder, and a contributing editor at Sky & Telescope magazine.
"This connection of Earth and sky is actually quite real, if not always so apparent. The Earth is in space, and we are traveling through the galaxy upon it. Giving me a sense of our status as space travelers is what I love about this image," Simmons said via email.
The bright city lights of Isfahan, Iran, become the gold at the end of the Milky Way's "rainbow" in an April 2010 picture. The image shows how light pollution can drown out even the dense gathering of stars in the galactic plane.
"I've seen the sky from within Isfahan's glow and from Iran's deserts. As in cities around the world, the city's inhabitants rarely know what they are missing," said Astronomers Without Borders' Simmons. "Perhaps this image will encourage them to leave the city and reconnect with the night sky."
Crisscrossing light trails create a visual cacophony over a bridge in Lisbon, Portugal, in a February 2010 long-exposure picture. Faint star trails and the thicker path of the crescent moon wheel toward the western horizon, while airplanes leave horizontal streaks of light as they fly to or from the Lisbon airport.
"This is a fascinating image because of all the action. But of course, action is not what the night sky is supposed to be about," said Astronomers Without Borders' Simmons.
"The stars are seen moving quite gradually as the Earth rotates, but the airplanes and cars scurry past, driven by the impatience of humanity. The stars do their best to stand out, but even the moon is overwhelmed by the myriad lights."
A July 2010 panoramic picture of the French island of Réunion captures the Milky Way over Piton de la Fournaise, or "peak of the furnace," an active volcano. The small island lies in the Southern Hemisphere, in the Indian Ocean off the coast of Madagascar.
The shot includes the constellation known as the Southern Cross at upper right, as well as the Small and Large Magellanic Clouds hovering at the lower right. These "clouds" are actually dwarf satellite galaxies of the Milky Way.
"Besides technical experience and a good DSLR camera with a fast lens, the successful [landscape astrophotography] image is always made when you are in the right place at the right time, and planning for this needs some knowledge about astronomy and sky-gazing," TWAN's Tafreshi said.
"The best landscape astropictures come from those with high interest and practical experience in astronomy."
Even the lights from small towns can block out views of the cosmos, as illustrated by a September 2010 panorama taken from the mountains on France's island of Réunion. As Venus twinkles brightly, colorful village lights stain the fog over a valley. Even on clear nights, the glare from those lights may mean only the brightest stars and planets are visible from the villages.
Astronomers Without Borders' Simmons notes that he's seen a similar view from the Mount Wilson Observatory, "a historic, once dark facility located above what is now the megalopolis of the Los Angeles area" in California. "The clouds don't usually keep the light entirely in check, but the sky does darken when the clouds are thick enough."
Seen in April 2011, a gate in the Great Wall of China "seems to echo the timelessness of the Milky Way above," Astronomers Without Borders' Simmons said. Built and rebuilt between the 5th century B.C. and the 17th century A.D., the Great Wall is actually a vast network of structures designed to impede foreign invaders. Despite its legendary longevity, the world landmark represents a blink of an eye in cosmic time.
"The Milky Way stood above this spot, just as in this image, long before this historic gate was built, and it will remain long after the gate is gone," Simmons said.
Light from Portland, Oregon—50 miles (80 kilometers) away—reflects off clouds in December 2010. Stars just manage to peak through the edges of the cloud cover.
Even when clouds aren't blocking the stars, "stray lights always brighten the sky to some extent," Astronomers Without Borders' Simmons said. "We can't control the weather, but we can keep our lights from shining upward, where it does us no good."
By honoring pictures of light pollution, the contest organizers hope to inspire people "to reclaim the night sky and its beauties, not only as a laboratory for astronomers, but as an essential part of our nature," TWAN's Tafreshi added.
Stars seem to spin around the celestial north pole in a December 2010 picture taken from the shores of California's Mono Lake.
Surrounded by limestone towers, the mineral-rich waters are home to many species of "extreme" bacteria, which can survive in conditions hostile to most other life on Earth—such as high heat or high acidity. The lake therefore acts as a living laboratory for scientists studying the types of life that might arise on alien worlds. (Related: "New Bacteria Makes DNA With Arsenic.")
"What would the night sky look like from the shore of an alien lake on a moon of Jupiter or Saturn? Except for the planets wandering about the sky, it would look just like this," Astronomers Without Borders' Simmons said.